It has long been known to equip valve surfaces used in fluid flow control equipment with gaskets formed of relatively soft rubber or similar elastomeric materials. In other applications it has been known to utilize more rigid synthetic plastics such as polytetrafluorethylene (PTFE) as a replaceable valve gasket component. See for example my U.S. Pat. No. 4,531,532.
Often gasket materials are selected on the basis of a compromise between a need for dimensional stability of the materials, usually provided by hard plastics or high durometer elastomers, and, on the other hand, the need for the sealing surfaces of the gaskets to be soft and compressible to provide good sealing efficiency. Other situations requiring compromise arise where, for example, the operating temperatures of the valve system are such that none of the existing materials are entirely suitable.
In view of these various limitations, a need has continued to exist for gasket materials which combine such advantages as dimensional stability, abuse tolerance, temperature stability and softness and compressibility.